A 3D model is made up of one or more polygons which define a subdivision surface. Subdividing the polygons increases the number of polygons in the 3D model and, thus, the granularity and the quality of the approximation of the surface represented by the 3D model. However, increasing surface granularity decreases rendering performance.
Uniform subdivision techniques subdivide each polygon in the 3D model the same number of times. By contrast, adaptive subdivision techniques subdivide different polygons in the 3D model different numbers of times.